iirc the specification states it’s 5 minute.
The user changed their twitch password
The user used the forgotton password routine.
The user unlinked their account
Something else happened to break links or tokens
You generated 51 tokens which killed token 1 and you still have token 1 in use somewhere due to how you are handling oAuth.
Are a few things that could result in access and/or refresh token death.